I am unsure what i am doing wrong for part B i have tried it

I am unsure what i am doing wrong for part B i have tried it a few times and am not getting the right answer for that problem but i am not sure where i went wrong at.

Problem 28.19 Part A A 2.8-cm-diameter parallel-plate capacitor has a 2.2 mm spacing. The electric field strength inside the capacitor is 1.5x 105 V/m What is the potential difference across the capacitor? Express your answer to two significant figures and include the appropriate units. Submit My Answers Give Up Correct Part B How much charge is on each plate? Express your answer to two significant figures and include the appropriate units. aal 6.045 10C Submit My Answers Give Up

Solution

a)

Potential difference across the capacitor

V=Ed =(1.5*10⁵)(2.2*10^-3)

V=330 Volts

b)

diameter d=2.8 cm

Area of capacitor

A=pi*d²/4 =pi*0.028²/4

A=6.16*10^-4 m²

Capacitance of the parallel plate capacitor

C=e_oA/d =(8.85*10^-12)(6.16*10^-4)/(2.2*10^-3)

C=2.477*10^-12 F

Charge on each plate of capacitor is

Q=CV =(2.477*10^-12)*330

Q=8.17*10^-10C